JP2022504815A - Systems and methods for determining tooth color, and attachments for use in the system - Google Patents

Abstract

The present invention relates to a system and method for determining the color of a tooth or tooth surface, wherein the system comprises a 2D or 3D camera and an attachment on the camera, the attachment capturing an image without the attachment. By comparison, the shape of the captured image is set so that the distance, spatial angle, and orientation of the tooth surface with respect to the camera are limited. The attachment according to the present invention can be fitted to the camera in a particularly simple manner.
[Selection diagram] Fig. 1

Description

The present invention relates to systems and methods for determining tooth color, as well as attachments for use in the system.

To date, color determination to determine an aesthetically matched shade of crown and tooth replacement has been predominantly performed using a similar process, where the practitioner is responsible for adjacent teeth or teeth to be replaced. Is compared to a particular color pattern (eg, VITA classical A1-D4® Shade Guide) and thus approaches a matching color. If this process is not performed correctly, it results in restorations that do not match the existing tooth condition in terms of color. If the restoration does not match in color, the work must be redone and a new patient appointment is required.

Perfect color reproduction has also become increasingly important to patients and is now part of a systematic process chain of color determination, color transfer, color reproduction, and color control.

This process involves many variables and sources of error such as practitioner eye fatigue, the effects of artificial lighting, etc. For this reason, devices that digitally determine tooth color have been developed specifically for color determination. Recently, it has become possible to measure tooth color using a 3D intraoral scanner. Such a 3D intraoral scanner is provided by Sirona Dental Systems GmbH, for example, under the name CEREC Omnicam.

Relatively expensive such 3D scanners, however, are not yet available in all dental offices. However, although most dental offices already have more affordable 2D intraoral cameras, color determination was previously impossible with them. Using a conventional intraoral camera, the dentist can take pictures and videos in the patient's mouth, but cannot determine the color. Also, there are currently various 3D intraoral cameras, but it is still impossible to determine the color with them.

WO 2018/08413 A2 describes a light blocking device that can be fitted to a camera or smartphone or tablet, and the tooth image data or tooth color recorded by the camera shall be compared to the reference tooth color. Can be done.

An object of the present invention is therefore to provide a simple, cost effective and easy-to-use system for accurately determining the color of teeth, especially tooth surfaces, for the manufacture of dental restorations. It is to be. Also provided is a method in which accurate determination of tooth color is easily possible. Further provided are attachments that can be used in systems for accurate color determination of tooth restorations.

This object is achieved by the systems, methods, and attachments specified in claims 1, 18, 23, and 25, respectively. In each case, a favorable further development of the invention is specified in the dependent claims.

According to the present invention, there is provided a system for determining tooth color, comprising a 2D or 3D intraoral camera and an attachment on the camera, the attachment being the distance from the camera to the tooth surface to be measured. The spatial angle captured by the camera, and the orientation of the tooth surface to be measured with respect to the camera, is captured so that it is limited compared to the use of the camera to capture images in a traditional fashion without attachments. Set the shape of the image.

A particular section of the tooth surface can therefore be captured, and the distance to the camera and its relative orientation to the camera are optimal for the color measurement process, which allows for a good determination of tooth color. To.

The shape of the recorded tooth surface, i.e., the distance from the camera to the tooth surface to be measured, the spatial angle captured by the camera, and the orientation of the tooth surface to be measured with respect to the camera are controlled by the attachment of the present invention. Tooth. The alignment, the position of the camera relative to the tooth surface, and the size of the captured surface are set in this way. Since a typical 2D camera also has an integrated illumination, the distance of illumination to the tooth surface and the direction of incidence on the surface and camera are also implicitly defined by the attachment.

An advantage of the present invention lies in the fact that 2D or 3D cameras already available in the dental office can be used for color determination. From this, the dentist can take advantage of affordable digital media that are already available in the dental office or integrated into the treatment unit and can be used in the system for color determination. He must always be brought into the treatment room and turned on, and in part he does not have to buy any other individual device that is very expensive to procure.

Tooth color measurements are performed using a 2D camera. At that time, unlike the case of color measurement using a 3D camera, the 3D shape is also not recorded and is not included in the color calculation. Instead, for attachments on a 2D camera, the alignment, the relative position of the camera, and the illumination to the teeth are the distance of the camera to the tooth surface, the captured spatial angle, and the orientation, along with the orientation of the illumination and detection sensors. Is also set to be limited compared to measurements taken by cameras that do not use attachments.

Tooth color measurements can also be performed using a 3D camera if the 3D camera is capable of simultaneously recording a 2D color image and 3D data. In particular, camera systems in which contrast agent powder is used for 3D measurements are generally not capable of correctly determining tooth color, so the use of attachments mentioned above in connection with 2D cameras is the use of tooth color. Is useful in determining.

The attachment comprises a spacer having a connecting means such as a click connection or a plug connection, especially for a simple fit to the camera. Therefore, it is advantageously possible to quickly and easily fit the attachment onto the camera for color determination.

On the spacer, the attachment specifically comprises an aperture in the form of a pinhole or slot aperture, through which the camera captures an image of the tooth. As a result of the spatial position of the aperture in the recording area of the camera, the distance to the camera, the captured spatial angle, and the orientation when placed on the tooth surface as desired to determine the tooth color. In addition, it is restricted in an advantageous manner.

The attachment specifically comprises, at least in part, a front-fitted silicone support. The silicone support can at least partially fit the tooth surface during placement, and as a result, it cannot slide away. By fitting flush onto the teeth, the silicone support can also prevent the entry of interfering scattered light, which ultimately allows for more accurate color determination of each tooth. As such, the captured color can then be used without further correction for tooth replacement color design.

The spacer specifically comprises an imaging optical system, which is inserted into a pinhole or slot aperture or placed behind the pinhole or slot aperture. The imaging optical system can advantageously magnify the image of the captured area on the detection sensor of the camera. The color information from the pinhole can be magnified from this, and thus can be measured using a larger number of pixels, and more robust results can be achieved. The imaging optics can optionally be fully filled with pinholes or slot apertures. According to the present invention, however, an imaging optical system is not always necessary.

The system comprises means for color calibration, in particular with software and / or hardware. The system is advantageously calibrated by the software, which is provided separately from the system and either added to the system or installed in the system as a software module.

Hardware means specifically means providing a color pattern consisting of reference colors. However, it is also possible to use only white as the reference color.

The system receives input data, in particular, as a color image captured by a camera or as image-based data. The captured image can thus be advantageously processed and used for color determination.

The system specifically detects changes in the image field captured by the camera and, as a result, switches to color measurement or color measurement mode. Color measurements can therefore be performed advantageously quickly and without additional intermediate steps.

In that system, color measurements are specifically initiated automatically or by footswitches. In the system according to the invention, color measurement is therefore advantageous, either intentionally when the footswitch is operated, or automatically when vibration is not detected by the 2D camera or when uniform color is detected. Can be started in.

The system analyzes the acquired data, especially based on color calibration, and outputs the results in the standard colors of the manufacturer of the tooth replacement material. Color selection for tooth replacement materials can, from this, be performed automatically in an advantageous manner.

The system specifically comprises a color calibration set with a target color for calibration. The color calibration set is preferably designed as a color pattern with various target colors for calibration. Such a color pattern is preferably installed inside the attachment, especially in the immediate vicinity of a pinhole or slot aperture. By providing such a color calibration set, color matching of the captured image, including calibration, can be performed in parallel each time the tooth color is recorded via a pinhole or slot aperture. Over time and temperature effects, the latter being caused by a light source inside the camera, the time and temperature effects can be compensated or compensated for, for example, by a color calibration set installed inside the attachment. For example, the effects of the camera's image sensor over time can also be compensated or corrected in this way. Changes in the system, in particular over time, can also be compensated or compensated for by an external color calibration set.

The present invention further provides a method for color determination for tooth restorations, the attachment is fitted to a 2D or 3D camera, and the shape of the image to be captured is from the camera to the surface to be measured. A specific section of tooth shape or image of a tooth that is set by the attachment to limit the distance, the orientation of the surface to be measured with respect to the camera and lighting, and the spatial angle for capture. It is captured in the oral cavity by a camera linked with the attachment.

By fitting the attachment and then setting the shape of the image to be captured by the camera, existing 2D or 3D cameras can be advantageously used to accurately determine tooth color.

Color calibration is performed specifically by capturing images consisting of different reference colors. Target / actual comparisons can be performed using known reference colors and any deviations can be compensated or corrected.

The reference color for color calibration is preferably obtained immediately before, during, or immediately after each color determination for the tooth, and as a result, system calibration can be performed in substantially real time. In such cases, the reference color is integrated into the attachment. The system can, as an alternative, be calibrated at time intervals without performing color determination on the teeth immediately before, during, or immediately after. To do this, attachments provided with reference colors are preferably placed on the camera at predetermined intervals, eg, one week apart, to perform calibration.

The acquired data is analyzed, in particular, based on color calibration, and the results of the analysis are output in the manufacturer's standard color of the tooth replacement material. The color selection for the tooth replacement material can, in this way, be carried out automatically in an advantageous manner.

The invention further provides an attachment for use in a system according to the invention, which is via a pinhole or slot aperture with a spacer and a connecting means for fitting the attachment onto a 2D or 3D camera. The camera comprises a pinhole or slot aperture to capture the image of the tooth, and the spacer creates a distance between the camera's capture device and the pinhole or slot aperture.

Attachments can be fitted favorably to existing cameras without much effort and can be used in conjunction with existing cameras for accurate color determination for tooth restoration.

Further, in an alternative embodiment of the system described above, the attachment is a holder in which the camera has at least one camera opening and the attachment is around the at least one camera opening, at least one. A holder that provides a light-tight connection to an area of one camera opening and a holder that is light-tightly connected to the holder and has at least one front side to at least one camera opening at the tip of the attachment's optical path to at least one camera opening. The adapter may be characterized by comprising at least one aperture and / or an adapter with an opening and a support at least partially adjacent to the aperture. This embodiment provides the advantage that different adapters with different apertures and / or color reference patterns can be attached to the holder, for example, but not limited to them. Further, the light-tight connection of the holder to at least the circumference of at least one camera opening prevents light from sources other than the internal camera illumination from interfering during the color determination process.

As mentioned above, and within this or other embodiment of the invention, the holder is attached to the camera by a clamp and / or latch and / or slide and / or click and / or ring and / or plug mechanical element. Attached and / or the holder is detachably connected to the camera.

In particular, the holder comprises at least a holder opening corresponding to at least one camera opening and at least one support surface and / or foam fit profile according to the shape of the casing in which the at least one camera opening is located. Can provide a light-tight connection to at least one camera opening, and at least one support surface and / or foam fit profile allows the correct positioning of the attachment on the camera corresponding to at least one camera opening. To.

In addition, the adapter may include at least one color reference pattern facing at least one camera opening, preferably located next to or around the front aperture and / or opening.

Moreover, within the aforementioned alternative embodiments or other embodiments of the present invention, the at least one aperture and / or opening can have a different shape, preferably a rectangular or circular shape, and / Alternatively, it has a cross-sectional area of 0.5 cm ² or less, preferably less than 0.35 cm ² , or even more preferably less than 0.15 cm ² but 0.01 cm ² or more.

Generally, in the present invention, at least one support is
-With an elastic material, preferably a silicone and / or an elastomer,
• Surrounds at least one aperture and / or opening in the circumferential direction and / or
-Part of the anterior side, the anterior side being at least partially made in the area of soft and / or elastic material and / or
The anterior side is formed from at least two layers, the at least layer facing the tooth surface is made of an elastic or soft material, preferably an elastomer or a soft plastic, and / or
• Recessed or protruding in the front and / or
-Preferably at least one area on the anterior side provided with contours, preferably ruffled and / or other friction or grip augmentation contours.

In addition, the alternative embodiments described above, however, the other embodiments according to the invention may also include an attachment comprising a transition piece as a spacer, the spacer.
It is a separate component that is optically tightly connected to the adapter and holder by a connecting means, or
-Partially composed of adapters and holders, or
• Completely configured with adapters or holders, or
-Consists of a single component element that acts as an attachment with holders, spacers, and adapters.

Preferably, the adapter, holder, and / or spacer connecting means are formed and / or removable as mechanical elements of clamps and / or latches and / or slides and / or clicks and / or rings and / or plugs. be.

Finally, the spacer length of the embodiments according to the present invention is such that the color reference pattern and / or the aperture is located near the optical focal plane of the camera, preferably within the optical focal plane of the camera. Can be adjusted with respect to the surface.

In the system, method, and design according to the present invention, accurate color determination can be easily performed without the need for a large investment by the user.

Specific and further features and details of the invention will be apparent to those skilled in the art from the embodiments and accompanying drawings for carrying out the following inventions that demonstrate the features of the invention based on examples.

A general design of a system according to the invention with attachments including spacers, connecting means, and pinhole apertures is shown. The pinhole aperture according to the present invention is shown. The pinhole aperture which has the silicone support which concerns on this invention is shown. A pinhole aperture having an imaging optical system according to the present invention is shown. The pinhole aperture and the color calibration set which concerns on this invention are shown. The schematic diagram of the system which concerns on this invention is shown. FIG. 6 shows an enlarged view of the attachment of the system shown in FIG. 6a, having a holder, spacer, and adapter. A schematic cross-sectional view of the attachment adapter when placed on the teeth is shown. FIG. 7 shows a schematic cross-sectional view of FIG. 7 for another embodiment having different optical axes with respect to the tooth surface. FIG. 3 shows a perspective view of an attachment adapter with a circular / pinhole aperture. A perspective view of an attachment adapter having a rectangular / slot aperture is shown. FIG. 3 shows a schematic view of the front of an attachment adapter having a support that surrounds the aperture in the circumferential direction. FIG. 3 shows a schematic view of the front of an attachment adapter with a support adjacent to an aperture with a circular base. FIG. 3 shows a schematic view of the front of an attachment adapter with a support adjacent to an aperture with a rectangular base. A side view of the holder of the attachment demonstrating the fixation and location of the camera in it is shown. A side sectional view of the holder is shown. The rear view of the holder is shown. The top view of the holder is shown. A perspective view of the holder is shown, and the front thereof is shown. A perspective view of the holder is shown, and the back surface thereof is shown.

The present invention uses preferred embodiments and is described in detail below with reference to the drawings.

FIG. 1 shows a general design of a system according to the invention for determining the intraoral color of a tooth or tooth surface using a camera 1 and an attachment 10. As can be seen in FIG. 1, the attachment 10 includes a spacer 2, a connecting means 3, and an aperture 4. Aperture 4 is preferably configured as a pinhole aperture. A slot aperture (not shown) can also be provided as an alternative. On the front side facing the object to be measured, the attachment 10 can be provided with a silicone support as described below.

Cameras already available in the dentist's office, especially 2D cameras, can be used for color determination. From this, the dentist can utilize a digital medium that can be used in the system for color determination, which is already integrated in the treatment unit. He must always be brought into the treatment room and turned on, and in part he does not have to buy any other individual device that is very expensive to procure.

The attachment 10 can also, in principle, be used with a 3D camera if the 3D camera is capable of capturing 2D color images. Especially in 3D camera systems that use contrast powder for 3D measurements, attachments are a true value because these camera systems are not otherwise capable of determining tooth color with sufficient accuracy. Will be provided.

The tooth color measurement is preferably performed using the 2D camera 1 and unlike the color measurement using the 3D camera, the 3D shape is also not recorded and is not included in the color calculation. Instead, in the attachment 10 on the 2D camera 1, the shape is set so that the camera's distance, spatial angle, and orientation with respect to the surface to be captured are limited compared to measurements made by a camera without an attachment. Will be done.

Tooth color measurements can also be performed using a 3D camera if the 3D camera is capable of capturing 2D color images. In particular, camera systems in which contrast powder is used for 3D measurements are generally not able to correctly determine tooth color, so the use of attachments described in connection with 2D cameras is tooth color. Is useful in determining.

The attachment 10 comprises a spacer 2 having a connecting means 3 such as a click connection or a plug connection, especially for a simple fit to the 2D camera 1. From this, the attachment 10 can be quickly and easily fitted onto the 2D camera 1 for color determination.

On the spacer 2, the attachment 10 comprises an aperture 4 in which the 2D camera 1 captures an image of the tooth via the aperture 4. The aperture 4 is provided to advantageously limit the distance and angle captured, as desired for tooth color determination.

In each case, the aperture 4 is configured away from the surface to be measured so that the captured surface is smaller than one of the smaller teeth, preferably less than half the average surface of the incisors. Be separated. In general, the system can be used to capture the color of all teeth, such as incisors, canines, or molars. The captured surface is preferably less than 0.5 cm ² . The captured surface is particularly preferably in the range of 0.15 to 0.3 cm ² . Even so, the captured surface limitation ensures that only the tooth surface itself is captured and that nearby areas such as gingiva or transdental areas that can distort the result are not captured. Intended. The use of pinhole apertures is preferred, and in some cases it is certainly possible to use apertures designed as slot apertures, for example, when the color gradient of the tooth surface is measured.

When the attachment is used in the system according to the invention, the spacer 2 creates a defined distance between the capture device of the camera 1-the sensor and the optical system-and the aperture 4. Placing the attachment on the tooth to be measured also sets the angle between the tooth surface and the camera. When the attachment is placed flat on the tooth to be measured, the tooth surface is approximately parallel to the focal plane of the camera, thereby allowing deviations of up to about 30 °, and therefore tooth color. A sufficiently accurate capture of is generally possible. The attachment should be placed so that during the measurement, the tooth surface to be measured is centered under the aperture, and thus in the center of the camera image.

It should also be noted that for illustration purposes, the deflection mirror is typically a component of a 2D or 3D intraoral camera. They deflect the imaging beam path by a fixed angle (107 ° in the case of CEREC Omnicam specified above). The angle set by the attachment according to the present invention is the angle between the central beam of the imaging optical system and the surface to be measured. For brevity, however, in this case we refer to it as "the orientation of the surface to be measured with respect to the camera". When the attachment is placed on the tooth on its flat side, the surface to be measured is in the defined orientation with respect to the camera. The spatial angle at which the camera can capture image data is also limited by the aperture.

FIG. 2 shows a single aperture in the form of a pinhole aperture 4.

FIG. 3 also shows a pinhole aperture 4 provided with a silicone support 5, unlike the pinhole aperture of FIG. Except for the aperture opening, the silicone support 5 can completely (not shown) or partially cover the pinhole aperture 4.

Since the aperture 4 forms the front end of the attachment 10 (FIG. 1), the silicone support 5 of the aperture rests on the tooth when the attachment is placed on the tooth and at least partially on its surface. It fits and, as a result, it cannot slide away, on the one hand. On the other hand, by fitting flush over the teeth, the silicone support can prevent the entry of interfering scattered light, which ultimately allows for more accurate color determination of each tooth. Therefore, the captured color can then be used for tooth replacement color design without further correction. Finally, the placement of the attachment also sets the angle between the tooth surface and the camera. When the attachment is placed on the tooth to be measured, the tooth surface is approximately parallel to the focal plane of the camera, so that deviations up to about 30 ° do not significantly affect the results. When the attachment is placed over the tooth, the depth of the tooth surface is approximately in the focal plane of the camera's imaging optics.

The spacer 2 may be provided with imaging optics 6 (not shown), which may be inserted, for example, into a hole in a pinhole aperture or placed behind a pinhole or slot aperture. The imaging optical system can advantageously magnify the image of the captured area on the detection sensor of the camera. From this, color information can be measured using a larger number of pixels and more robust results can be achieved. The imaging optics can optionally be fully filled with pinhole apertures. By using the imaging optical system 6, more and / or better data can potentially be obtained than without the optical system.

According to the present invention, the system may further comprise a means for color calibration, which means may include software and / or hardware. The hardware preferably comprises a color calibration set with reference colors for calibration. The color calibration set is specifically designed as a color pattern with various target colors for calibration. Such a color pattern is preferably installed inside the attachment, especially in the area of the pinhole or slot aperture. By providing such a color calibration set, color matching, including calibration, of the captured image can be performed in parallel by the software each time the tooth color is recorded via a pinhole or slot aperture. .. Over time and temperature effects, the latter being caused by a light source inside the camera, the time and temperature effects can be compensated or compensated for, for example, by a color calibration set installed inside the attachment. For example, the effects of the camera's image sensor over time can also be compensated or corrected in this way.

Changes in the system, in particular over time, can also be compensated or compensated for by an external color calibration set. To do this, the system can be equipped with an additional attachment, which is provided with a reference color and placed on the camera at predetermined time intervals, eg, weekly intervals, thereby. Perform calibration. The measured values are then stored by the software for use as comparison values for tooth color measurements.

Well-defined color patterns (reference colors) are typically used for calibration, and in the next step, the parameters involved in the system's color perception are corrected / optimized by target / actual adjustment. To.

The system specifically analyzes the data acquired during tooth color measurements based on color calibration and outputs the results in the manufacturer's standard colors for tooth replacement materials. Color selection for tooth replacement materials can, from this, be performed automatically in an advantageous manner.

A known color scale (eg, Vita Shade Guide) is used to classify different tooth colors, and the software stores "learned" color information during color pattern / reference color measurements.

The color measured by the camera's image sensor is a function of a variety of different system characteristics. The most important ones are:
-Light source brightness and spectrum,
-Distance from light source to surface and surface tilt with respect to light source,
-Surface position and alignment in the measurement field of the sensor,
-Effects of sensor and LED over time and temperature.

It makes sense to calibrate the system in the manner described above, in particular, to allow it to take into account the parameters that change or can change over time among the parameters described above. .. More simply, the intent is to compensate for temporal changes in the color measurement characteristics of the system by calibration. The system further comprises attachments with different attachments, eg, different apertures and / or different coverage angles and / or different optics and / or different sized coverage surfaces and / or different silicone attachments (eg, for different teeth). It can also be designed to be prepared. To this end, the system can be designed so that it automatically calibrates for each attachment, which is specifically the aforementioned real-time calibration using a reference color integrated during the attachment. In the context of, it is easy to achieve.

The system receives the input data as an image captured by the camera 1 or as data based on the image captured by the camera 1. The captured image can thus be advantageously processed and used for color determination.

The system can further detect changes in the image field captured by camera 1 and, as a result, switch to color measurement mode. Color measurements can therefore be performed advantageously quickly and without additional intermediate steps. In that system, color measurements are also initiated automatically or by footswitch. Therefore, in the system according to the present invention, the color measurement is intentionally advantageous when the foot switch is operated, or automatically when vibration is not detected by the 2D camera 1 or when uniform color is detected. Can be started.

Based on color calibration, the system analyzes the acquired data and outputs the results in the manufacturer's standard colors for tooth replacement materials. This can be done by software. The color selection for the tooth replacement material can from this be done automatically.

To calibrate the system in the manner described above, the aperture 4 of the system may be provided with a color calibration set 7 consisting of reference colors inside it. The system for color determination according to the present invention requires color calibration at regular intervals to compensate for small deviations in the illumination spectrum and imaging system. Target colors are typically recorded within the context of such color calibration. These make it possible to adjust the system response by calibration. In the color calibration set 7 described above, the reference color is applied to the inside of the aperture 4. In this way, it is possible to perform color matching including calibration of the captured image for each tooth color recording by the aperture 4.

A method for determining the color of a tooth or tooth surface first comprises fitting the attachment 10 to a 2D camera 1. FIG. 1 shows a system according to the invention after this step has been performed. The shape of the image to be captured is then set by the attachment 10 so that the distance, orientation, and spatial angle for capturing the image are limited for the camera with respect to the tooth surface to be measured, and the shape of the tooth. An intraoral image of a particular defined section or tooth is later captured by the 2D camera 1 in conjunction with the attachment 10.

In cases where only monochromatic ceramics are used as tooth restoration materials, a single image acquisition or measurement is sufficient. However, if, for example, the use of a multicolored restoration material having a color gradient is intended, as many measurements as necessary for color determination can be performed using the system according to the invention.

It should be further noted that the tooth color is determined from the recorded image data, for example using statistical analysis such as averaging. In particular, image data recorded from inside the (pinhole) aperture is advantageously used for this purpose.

Color calibration is performed by capturing the image and comparing the data in the captured image with the predefined or acquired color data, which is either predefined by the software or on the attachment 10. Based on the acquired data of a color calibration set 7 having a reference color for calibration provided inside the aperture 4 of the above (see FIG. 5).

The data in the captured image is analyzed based on color calibration and the results of the analysis are preferably output in the standard color of the manufacturer of the tooth replacement material so that the data has the appropriate color variants. No further treatment is required before the restoration material can be selected by the practitioner / dentist.

The system is preferably designed so that it recognizes the presence of an attachment on the camera. This can be achieved, for example, based on changes in the image field captured by the 2D camera 1, which will result in an automatic switch to color measurement. Switching can also be accomplished, possibly via a user-initiated command.

Referring to FIG. 6a, here is a schematic diagram of the process of color determination of the tooth 40 by the system described above according to the present invention. A camera with a central axis 34 has a camera opening 37 with an optical axis 35 that includes an angle in the range 75-135 ° with respect to the central axis 34, where 90 ° in the schemes 6a and 6b. The angle of is shown. The optical axis of the camera opening (see FIG. 6b) and the optical axis of the attachment are on the same line and are shown as one axis 35 in FIG. Optical close contact of the attachment to the circumferential area with respect to the camera opening 37 is provided by the support surface 33, which is due to the camera 1 in which stray light or light from other than the light source of the camera 1 is combined with the attachment 10. Prevents interfering with or interfering with color determination. Another realization of light-tight contact with at least the surrounding area of the camera opening 37 can be provided by the foam-fitting shaped portion of the attachment 10.

The aperture 4 in the attachment 10 defines the attachment optical axis corresponding to the optical axis 35 of the camera opening 37. Further, in the field of view of the camera light source and the illumination cone 36, at least one color calibration pattern 7 is located inside the attachment 10. In the case of FIG. 6a, the pattern 7 is located in the same plane and adjacent to the aperture 4. On the outside is provided with at least one support 5 for a determined and stable contact to the surface 41 of the tooth 40 whose color should be determined. The support 5 can be, for example, the silicone ring described above.

Within this configuration, the light cone 36 illuminates the tooth surface 41, its color is evaluated, and at the same time the reference color pattern 7 is evaluated, from which, as described above, the tooth according to the image recorded by the camera 1. Allows referenced or directly calibrated color determination of surface 41.

FIG. 6b shows an enlarged cross-sectional view of the attachment 10 of FIG. 6a. The optical axis 35 of the camera opening 37 and the optical axis 35 of the attachment 10 are on the same line, which allows them to be represented as one axis, at the same angle with respect to the camera center axis 34, in this case. Has 90 °. In this embodiment, the attachment 10 is connected to the camera 1 via three components, namely the connecting means 3 (not shown in FIG. 6b), and the support surface 33 around the corresponding holder opening 30'. A holder 30 that provides at least light-tight contact to an area in the circumferential direction with respect to the camera opening 37, as shown by, and the aforementioned aperture 4 and color reference pattern 7 inside the tooth surface during use. A transition piece or spacer 2 that provides an adapter 20 on the outside with a support 5 on the side facing the camera and a corresponding distance for the adapter 20 to the camera aperture 37 with respect to the correct imaging distance for the built-in camera optics. And prepare. The spacer 2 provides at least a color reference pattern 7 and optionally an aperture 4 located near the focal plane of the camera 1. The color reference pattern 7 and the aperture 4 are preferably located on the focal plane of the camera 1. All components are detachably connected so that, for example, the different spacers 2 according to the invention corresponding to different camera optics and / or models are the correct spacing of the adapter components 20 with respect to the focal plane of the camera 1 used. Can be used to provide.

Similarly, this also applies to the holder 30 and the adapter 20, for which different adapters 20 with different apertures 4 can be used, while in the case of the holder 30, for different camera bodies. Different holders can be provided. The connection between these elements is formed, for example, as a light-tight connection such as a slide mechanism, clip mechanism, or engagement mechanism, from which the color reference pattern 7 and the tooth surface 41 passing through the aperture 4 are uncontrolled and / Or prevent unspecified irradiation. In an alternative embodiment, the spacer 2 can be part of either the holder component 30 or the adapter component 20, or a partial part of both components. Further, a complete attachment can be provided as a single component element.

A more detailed presentation of the interaction of the attachment 10 on the tooth surface 41, in particular the adapter 20, is shown by the schematic cross-sectional view of FIG. As shown in the embodiment of the adapter 20 of FIG. 7, the aperture 4 has a defined diameter d that determines the actual illuminated area on the tooth surface 41, which is used for color evaluation. Will be done. Here, the cross-sectional area of the aperture of at least 0.5 cm ² or less, less than 0.35 cm ² or less than 0.15 cm ² is preferable, and the minimum area is 0.01 cm ² or more. This area provides a first approximation in the corresponding illuminated surface area of approximately the same size on the tooth 40 due to the short distance between the aperture and the tooth surface 41 with respect to the divergence of the optical system. However, these values serve as a guide for those skilled in the art.

The specific area of the aperture depends on the resolution and contrast capability of the camera and the corresponding intensity of the light source. Further, the support 5 is in contact with the surface 41 of the teeth 40 and provides a defined orientation in the space of the adapter and thus for the system with the attachment 10 and the camera 1. In the case of FIG. 7, the attachment optical axis 35 is parallel to the normal vector n of the tooth surface 41.

A different embodiment is shown in FIG. 8, where the attachment optical axis 35 is angled with respect to the normal vector n of the tooth surface 41. However, in both embodiments, the defined orientation of the attachment 10 with respect to the tooth 40 to be evaluated in terms of color, in particular the tooth surface 41, is established by the support 5 in combination with the adapter 20.

FIG. 9 shows a perspective view of the attachment adapter. The adapter 20 includes a front side 21 that defines the tip of the optical path with respect to the camera opening of the attachment 10. On the front side 21, an aperture 4 having a circular base and a color reference pattern 7 for color determination are located. Further, the adapter comprises connecting means 22, which is with their relatives on the holder 30 shown in the holder embodiments of FIGS. 14-17, or in the case of the attachment 10 with three components. A light-tight connection is provided with each relative on the spacer 2. A support 5 (FIGS. 7 and 8) is located outside the front side 21 (not shown in FIG. 9).

A different embodiment of an adapter with an aperture having a rectangular / slot shaped base that allows the color gradient on the tooth surface to be determined is shown in FIG.

11-13 show different embodiments of the support 5 on the outside of the front 21 of the adapter 20. FIG. 11 shows an embodiment in which the support 5 surrounds the pinhole aperture 4 in the circumferential direction, which advantageously provides light-tight contact to the tooth 40, which is any of the tooth surface 41. It also prevents secondary irradiation or prevents any stray or other unwanted light from entering the attachment through the aperture 4 and interfering with color determination. Such a support can be realized by the silicone ring described above or another elastic material or elastomer.

FIG. 12 shows an embodiment having a plurality of supports 5 having a rounded base, where the support 5 is located adjacent to the aperture 4. FIG. 13 shows an embodiment having a rectangular / slot formed aperture 4 and a corresponding rectangular base shaped support 5.

In general, all these configurations of FIGS. 11-13 described above also have the support partially recessed or projecting into the anterior 21 or partially or completely part of the anterior 21 itself. Can include being. The area of the anterior side 21 can be provided with elastic material and / or increases onto the tooth surface 41, for example, as the area shown as the base area of the support 5 in the anterior side 21 in FIGS. 11-13. It can be ruffled or otherwise contoured to provide grip. The anterior side can also be formed by two layers, the outer layer facing the tooth surface 41 can be elastic, which makes it stable with respect to the orientation of the attachment 10 with respect to the tooth surface 41. And provide the determined contact. In addition, the anterior side serves as the support itself without any of the modifications described above, as friction and surface pressure can provide sufficient defined and stable contact to the tooth surface. be able to. However, in this case, if the material of the anterior surface 21 is made of a soft or partially elastic material such as flexible plastic, a stable and determined contact enhancement with respect to the orientation of the attachment to the tooth surface 41 is achieved. be able to.

FIG. 14 shows a side view of the holder 30 of the attachment 10. The adapter 20 shown above is directly connected to the holder via the connecting means 32 and 32', or is shown in FIG. 6b for the corresponding connecting means of the spacer 2 (in the case of an attachment 10 having three components). ) Is either connected. The optical close connection is provided by engagement of the adapter connecting means 22 with the corresponding relatives 32 and the additional connecting means 32'of the holder. This, on the one hand, allows, for example, for different camera bodies, for example, to use different adapters with different apertures in combination with different holders, in the case of the attachment 10 with three components (FIG. 6b). See), allowing different spacers 2 to be used, while at the same time preventing ambient light from the surrounding environment from interfering with color determination. The holder 30 itself is connected to the camera 1 by the connecting means 3. In this embodiment, the holder 30 is an attachment corresponding to the angled optical axis of the camera opening 37 (FIG. 6b) of a camera such as the applicant's CEREC Omnicam having an angle 31 of 107 degrees with respect to the camera central axis 34. Adjusted to provide the optical axis 35.

15-17 show different views of the holder of FIG. 14, where the support surface 33, in particular, is shown. These surfaces provide light-tight contact of the attachment to camera 1 (not shown), especially around the camera opening 37 (not shown). Connection means 32 and 32'are also shown, which are formed as elements for the latch 32'and slide 32 connection between the adapter 20 and the holder 30. Further shown is the attachment of the holder, and thus the connecting means 3 that provides the camera with a complete attachment. In this embodiment, the connecting means 3 is formed as a ring clamp mechanism, which in this case has a diameter smaller than the diameter of the rod-shaped camera body. Other possible connections can be click connections or plug connection mechanisms. 18 and 19 show perspective views of the holder of FIG.

In the design and discussion so far, it is assumed that the camera of the system is provided with a light source to illuminate the teeth to be measured and, if applicable, the reference color pattern.

The present invention provides systems and methods for accurately determining tooth color, which are simple in design and easy to use. Further, according to the present invention, there is provided an attachment that can be easily used in the system of the present invention.
[Reference code]

1 Camera 2 Spacer 3 Connection means (to camera) 4 Aperture 5 Support 6 Imaging optical system 7 Color calibration set / color reference pattern 8 Spacer connection means 10 Attachment 20 Attachment adapter 21 Front side of adapter 22 Connection means 30 Attachment Holder 30'Holder opening 31 Angle between the optical axis of the attachment and the camera axis 32, 32' Connection means 33 Support surface (one or more)
34 Camera center axis 35 Attachment optical axis / Camera opening Optical axis 36 Irradiation cone 37 Camera opening 38 Focal plane 40 Tooth 41 Tooth surface

Claims (33)

A system for determining tooth color, comprising a 2D or 3D camera (1) and an attachment (10) on the camera (1), wherein the attachment (10) is defined above the tooth. Due to the arrangement, the attachment (10) is placed on the teeth and connected to the camera (1) as compared to the normal recording mode of the 2D or 3D camera (1) without the attachment. A system that sets the shape of an image captured by the camera (1) so that the image recording shape is defined by the attachment. The image recording shape is
The distance between the tooth surface and the camera,
The spatial angle captured by the camera and
The system of claim 1, wherein the orientation of the tooth surface to be measured with respect to the camera is limited. The system of claim 1 or 2, wherein the distance and orientation or alignment between the tooth surface and the exit surface of the camera is defined and set. The attachment (10) is characterized by setting the shape of the image captured by the camera so that the defined arrangement on the tooth also limits the size of the tooth surface to be measured. The system according to any one of claims 1 to 3. The attachment is characterized by comprising a spacer (2) having a connecting means (3) such as a click connection or a plug connection for easy attachment to the camera (1). The system described in any one of them. The attachment (10) on the spacer (2) comprises an aperture (4) in which the camera (1) captures an image of the tooth via the aperture (4), in particular a pinhole aperture or a slot aperture. 5. The system according to claim 5. The system according to claim 6, wherein the attachment (10) is provided with a silicone support fitted to the front side thereof at least partially. The system according to claim 7, wherein the aperture (4) is arranged on the front side of the spacer (2), and the silicone support (5) is provided at least partially. The system of claim 8, wherein the spacer (2) comprises an imaging optical system (6) incorporated into or behind the aperture (4). The system according to any one of claims 1 to 9, wherein the system comprises software and / or hardware means for color calibration. 10. The system of claim 10, wherein the hardware means comprises a color pattern comprising reference colors. 11. The system of claim 11, wherein only white is used as the reference color. The system according to any one of claims 1 to 12, wherein the system receives input data as an image captured by the camera (1) or as data based on the image. system. The system according to any one of claims 1 to 13, wherein the system recognizes a change to an image field captured by the camera (1) and then switches to a color measurement mode. .. The system according to any one of claims 1 to 14, wherein the color measurement can be started automatically or by a foot switch. One of claims 1-15, wherein the system analyzes the data acquired based on the color calibration and outputs the result in the standard color of the manufacturer of the tooth replacement material. The system described in the section. The system of claim 6, wherein the aperture (4) of the system comprises a color pattern comprising a reference color inside thereof for calibration. A method for determining tooth color, the following steps,
Fitting the attachment (10) to a 2D or 3D camera (1)
Placing the attachment (10) on the surface of the tooth to be recorded so that the tooth is located below the attachment (10).
Intraoral capture of a specific section of the tooth shape or an image of the tooth by the camera (1) in cooperation with the attachment (10).
Comparing the acquired data with the reference data and allocating the acquired data to the reference color,
How to prepare. 18. The method of claim 18, wherein the color calibration is performed by capturing an image consisting of different reference colors. The reference color is obtained immediately before, during, or immediately after each color determination for the tooth, thereby performing calibration of the system, or the system is color determining immediately before, immediately after, or simultaneously with the tooth. 19. The method of claim 19, wherein the method is calibrated at time intervals by reference colors without the need for execution. 20. The method of claim 20, wherein the captured image data is analyzed based on the color calibration and the result of the analysis is output in the standard color of the manufacturer of the tooth replacement material. 18. The arrangement of the attachment (10) on the surface of the tooth to be recorded is performed such that the tooth is located below the aperture (4) of the attachment (10), claim 18. the method of. An attachment (10) for use in the system according to any one of claims 1 to 16, wherein the camera (1) is toothed via a spacer (2) and a connecting means (3). The camera (1) is provided with a connection means (3) for fitting the attachment (10) to capture an image, and the spacer (2) is provided with a capture device of the camera (1) and a tooth surface. Attachment (10) that creates a distance between them. The camera (1) comprises an aperture (4), in particular a pinhole aperture or a slot aperture, through which the camera (1) captures an image of the teeth via the aperture (4), and the spacer (2) is a capture device of the camera (1). 23. The attachment (10) according to claim 23, which creates a distance between the aperture and the aperture (4). The camera (1) has at least one camera opening (37) and the attachment (10).
-With a holder (30) around the at least one camera opening (37) that provides a light-tight connection to the area of the at least one camera opening (37). ,
-At least one front side (21) that is lightly connected to the holder and faces the at least one camera opening (37) at the tip of the optical path of the attachment (10) with respect to the at least one camera opening (37). The adapter (20) comprising at least one aperture (4) and / or an opening and a support (5) located at least partially adjacent to the aperture (4). When,
The system according to claim 1, wherein the color of the tooth (40) is determined. The holder (30) is attached to the camera (1) by a mechanical element of a clamp and / or a latch and / or a slide and / or a click and / or a ring and / or a plug (3) and / or the holder ( 30) The system of claim 25 for determining the color of a tooth (40), characterized in that it is detachably connected to the camera (1). The holder (30) follows the shape of the holder opening (30') corresponding to at least one camera opening (37) and the casing in which the at least one camera opening (37) is located. It comprises at least one support surface (33) and / or foam fit profile to provide a light-tight connection to said at least one camera opening (37) and said at least one support surface (33) and / or foam. The fit profile determines the color of the teeth (40), characterized by allowing the correct positioning of the attachment (10) on the camera (1) corresponding to the at least one camera opening (37). 25 or 26. The adapter faces the at least one camera opening (37), preferably at least one located next to or around the aperture (4) and / or the opening on the front side (21). The system according to any one of claims 25 to 27 for determining the color of a tooth (40), comprising one color reference pattern (7). The at least one aperture (4) and / or opening can have a different shape, preferably a rectangular or circular shape, and / or 0.5 cm ² or less, preferably less than 0.35 cm ² . Or even more preferably any of claims 25-28 for determining the color of the tooth (40), characterized by having a cross-sectional area less than 0.15 cm ² but greater than or equal to 0.01 cm ² . The system described in paragraph 1. The at least one support (5) is
(I) It comprises an elastic material, preferably a silicone and / or an elastomer.
(Ii) Surrounding the at least one aperture (4) and / or the opening in the circumferential direction and / or.
(Iii) Part of the anterior side (21), the anterior side (21) being made at least partially in an area of soft and / or elastic material and / or.
(Iv) The anterior side (21) is formed from at least two layers, at least the layer facing the tooth surface (41) is made of an elastic or soft material, preferably an elastomer or a soft plastic, and / or. ,
(V) Recessed or protruded into the front side (21) and / or
(Vi) To determine the color of the tooth (40), characterized by being at least one area of said anterior surface provided with contours, preferably ruffled and / or other frictional or gripping augmented contours. 25. The system according to any one of claims 25 to 29. The attachment includes a transition piece as a spacer (2), and the spacer (2) is
(I) It is a separate component optically connected to the adapter (20) and the holder (30) by the connecting means (8), or
(Ii) Partially composed of or composed of the adapter (20) and the holder (30).
(Iii) Completely configured by said adapter (20) or said holder (30) or
(Iv) A tooth (40) color characterized by being composed of an element consisting of a single component that serves as an attachment comprising a holder (30), a spacer (2), and an adapter (20). The system according to any one of claims 25 to 30 for determining. The connecting means (22, 32, 32') of the adapter (20), the holder (30), and / or the spacer (2) are clamps and / or latches and / or slides and / or clicks and / or rings and. / Or the system of any one of claims 25-31 for determining the color of a tooth (40), which is formed as a mechanical element of a plug and / or is removable. .. The spacer length is such that the color reference pattern (7) and / or the aperture (4) is located near the optical focal plane (38) of the camera, preferably within the optical focal plane (38) of the camera (1). 25-32 for determining the color of the teeth (40), characterized in that the camera (1) is adjusted with respect to the optical focal plane (38). The system described in paragraph 1.

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